I've had problem last week. I received my order and started with 4 pills and had the usual three or four normal/loose BMs the next day. The next night I took six and within an hour the rumbling started and I was at the toilet with liquified BMs every half hour until about three in the morning. I have taken Oxypwder before and what I did then was to start with two and gradually build up each night working towards 8 at the weekend. I have taken a break and will start again using this method as it works best for me.
Mind you, although I was awake most of that night I did feel the benefit of getting rid of all that stuff and have been having normal BMs x 2/3 each day since.